c# - 为什么此 Linq 代码总是抛出 System.StackOverflowException？

Question

 //A query to a local object
 var deletionCommands = commands
     .Where(a => a.Operation != Operation.Addition)
     .Select(a => new { a.Prestador.cod_prestador, a.Prestador.cod_desdobramento })
     ;
 //A Linq-To-SQL query
 var toDelete = db.Prestadors
     .Where(a => deletionCommands.Contains(new { a.cod_prestador, a.cod_desdobramento }))
     ;
 db.Prestadors.DeleteAllOnSubmit(toDelete);
 db.SubmitChanges();

唯一解决问题的是一个显式循环:

 foreach (var command in commands)
 {
    if(command.Operation != Operation.Addition)
    {
        var toDelete = db.Prestadors
            .Where(a =>
                a.cod_prestador == command.Prestador.cod_prestador &&
                a.cod_desdobramento == command.Prestador.cod_desdobramento
            );
        db.Prestadors.DeleteAllOnSubmit(toDelete);
    }
 }
 db.SubmitChanges();

Answer 1

这确实是一个错误，并在 LINQ 4.0 中得到纠正

http://damieng.com/blog/2009/06/01/linq-to-sql-changes-in-net-40

Query stability Contains now detects self-referencing IQueryable and doesn't cause a stack overflow

编辑 在 .NET 3.5 中解决问题:当使用“自动生成的值”= True 时，您必须将“延迟加载”设置为 False - 否则会出现递归错误。

EDIT2 上述解决方案无效。